1. Field of the Invention
The present invention relates to a natural language processing system, as well as to a natural language processing method, for processing entered natural language information and, more particularly, to a natural language processing system and method for recognizing or correcting natural language information.
2. Description of the Related Art
Natural language recognizing systems have been known such as an optical character reader (OCR), a voice recognition machine, or an on-line or off-line hand-written character recognition machine. Such known natural language recognition system employs a pattern matching technique in which a character is identified as a candidate character which is selected from a group of candidate characters and which exhibits the best pattern matching with the character to be recognized.
Systems also have been proposed and used for verifying whether a row of recognized characters form a valid word, by making a reference to a dictionary.
It is true that the recognition efficiency can be remarkably improved through restricting the recognition results to valid words. Practically, however, it is often experienced that two or more valid candidate words are presented as a result of the recognition and verification so that the identification of the word cannot be performed.
It is also to be pointed out that the known recognition systems, when attempting to identify a word, do not take into consideration that a row of characters entered is a part of phrase or sentence which is described in a certain language and that each kind of information in a given context is followed by a specific type of information in accordance with meaning and/or grammatical construction of the sentence.
Operations of known natural language systems are based on an assumption that the entered information is correct without doubt. This causes an impediment to the construction of a natural language recognizing/processing system in which the processing system performs processing on information which is output from the recognition system and which may contain an error.
It is considered that execution of processing for expecting correct information as the input to the processing system, based on knowledge of a specific domain or context, contributes to correction of entered natural language information, even when the entry is made through means other than a recognition system, e.g., a keyboard. For instance, any typographical error incurred during entry can be corrected without difficulty by using a simple interface which is designed to restrict the scope or type of the information to be entered.